Fabrication and thermomechanical characterization of a new Cu–Al–Ni–Mn–Ti shape memory alloy bolt

Abstract

Industry experts in product innovation are always developing proposals and more effective solutions appropriate to the needs of some high-tech industrial areas, creating advanced technologies that increase the reliability of systems used in these areas. In this context, advanced materials are frequently studied to obtain more reliability in bolted joints, avoiding problems, such as leaks in pipelines or constant maintenance. In this work, a novel superelastic bolt was developed from a Cu–Al–Mn–Ni–Ti shape memory alloy (SMA) to increase reliability in bolted connections. The superelastic phenomenon presented by SMA allows full or partial recovery of large strains, between 4 and 8 % in tensile mode. This capability can be useful for the development of various industrial applications, especially in areas that require new high-technologies such as aerospace, automotive, energy and oil and gas sectors. Thus, this paper describes the fabrication and thermomechanical characterization of a superelastic bolt from a copper based SMA. The selected Cu–Al–Mn–Ni–Ti superelastic SMA was processed using plasma melting followed by metal injection molding for minimizing bolt manufacturing machining steps. After the manufacture of the SMA bolt, it was carried out thermomechanical characterization using DSC thermal analysis and reversible tensile testing at increasing temperatures between 35 and 90 °C. The results show that the superelastic bolt has good mechanical properties, demonstrating a great capacity for strain recovery and energy dissipation by mechanical hysteresis.